Chronic consumption of alcohol is a major contributing factor in the pathogenesis of hemorrhagic and ischemic stroke, and appears to contribute to cognitive impairment in animals and humans. While we have shown that chronic alcohol consumption impairs nitric oxide synthase (NOS)-dependent responses of cerebral arterioles, cellular/molecular mechanisms by which alcohol consumption contributes to cerebrovascular dysfunction remain unknown. The central theme of our application is to determine the mechanisms contributing to impaired NOS activity and reactivity of cerebral vessels during alcohol consumption. This central theme not only involves an examination of the role of co-factors of NOS, as possible targets of oxidative stress, but also involves cellular pathways responsible for the genesis of oxidative stress to affect the influence of nitric oxide on cerebrovascular reactivity. We propose the following aims: In Specific Aim #1, we will establish the activation mechanism and signaling cascade for NOS in cerebral arterioles during chronic alcohol consumption. We will test the hypothesis that chronic consumption of alcohol alters the role of nitric oxide in the regulation of basal tone and reactivity of cerebral arterioles. In Specific Aim #2, we will identify the role of NOS co-factors in impaired responses of cerebral arterioles during chronic consumption of alcohol. We will test the hypothesis that co-factors for NOS may influence reactivity of cerebral arterioles during chronic alcohol consumption. In Specific Aim #3, we will identify the role of cellular oxidant and antioxidant networks in impaired NOS-dependent reactivity of cerebral arterioles. We will test the hypothesis that activation of key cellular oxidative pathways by chronic consumption of alcohol contributes to impaired NOS-dependent reactivity of cerebral arterioles. In Specific Aim #4, we will establish a relationship between impaired cerebrovascular reactivity to brain morphology during chronic alcohol consumption. We will test the hypothesis that chronic alcohol consumption produces morphological alterations in cerebral vessels/brain tissue that may correlate with impaired cerebrovascular reactivity. In summary, we propose to utilize in vivo approaches coupled with new and innovative biochemical/molecular/-genetic/morphological approaches to identify cellular mechanisms contributing to impaired reactivity of cerebral arterioles during alcohol consumption. These studies will provide valuable new insights and will lead to new therapeutic approaches for the treatment of cerebrovascular abnormalities observed in chronic alcoholics. [unreadable] [unreadable]